
$fn=100;
intersection(){
difference(){
    union(){
        difference(){
            cylinder(h=30,d1=220,d2=210);
            translate([0,0,2])cylinder(h=28,d1=217,d2=207);
        }
        translate([0,0,2])
            cylinder(h=28,d1=214,d2=204);
            
        
    }
    cylinder(h=30,d1=211,d2=201);
    }
cube([120,30,28]);
}